Application of VSD technique in adults with chronic osteomyelitis of the extremities combined with soft tissue defects

To investigate the clinical application of vacuum sealing drainage (VSD) in chronic osteomyelitis of the extremities combined with soft tissue defects in adults. This study retrospectively included 32 adult patients with clearly diagnosed chronic osteomyelitis of the extremities combined with local soft tissue defects, and the trauma was covered by VSD after debridement, osteotomy, and vancomycin-laden bone cement filling of the occupancy, and the trauma was covered by selecting a suitable flap transfer repair according to the site and extent of the soft tissue defect after the trauma condition was suitable, and the secondary trauma was taken from the abdominal full-thickness skin free skin slice graft, according to whether the skin graft area was performed. The skin flap hematoma and infection rate, as well as the skin flap survival rate and implant fixation time were compared and analysed between the two groups. The primary outcome is the implant fixation time, and the secondary outcome is the skin fragment survival rate. In 32 patients, VSD was performed on the bone cement surface to cover the trauma, and 33.2 to 39.8 kPa continuous vacuum sealing drainage was set. The average VSD time duration before soft tissue coverage was 47.87 ± 23.14 days, and the average number of VSD use was 7.18 ± 3.23. The use of VSD before soft tissue coverage did not cause complications such as negative pressure could not be maintained, vacuum sealing drainage was not smooth, skin blistering, trauma. Among the 32 patients, 12 cases of soft tissue coverage were followed by trauma free skin grafting with packing + VSD, and 20 cases were fixed with packing alone, and the duration of continuous packing and fixation of free skin pieces in the VSD group was significantly less than that in the control group (P = .006). The survival rate was significantly higher than that of the control group (P = .019). VSD in adult patients with chronic osteomyelitis of the extremities combined with soft tissue defects can effectively improve the trauma condition, provide the possibility of second-stage soft tissue coverage, and significantly shorten the preparation time for soft tissue coverage. In addition, when soft tissue coverage trauma is performed, VSD combined with skin graft packing technique can significantly improve the survival rate of skin pieces, shorten the time of skin graft fixation.     

Gewebereaktionen um gelockerte Hüftgelenkendoprothesen

Pseudocapsules and interface membranes from 142 consecutive revision surgeries of hip prostheses were histomorphologically analyzed including a semiquantitative grading of the wear particles from the prostheses and bone cement as well as the cell infiltrates. The implant duration varied between 3 months and 19.5 years. In 37% of the cases up to 6 months in situ, inflammatory cell infiltrates characteristic for early infection were seen. In 22% of the cases with longer implant duration, signs of late infection were found. In the tissues of the predominantly cemented prostheses, bone cement wear prevailed, which could be regularly detected after about 1 year. Polyethylene wear appeared to be the second most common foreign material. Metallic wear was found in only 18% of the cases. Ceramic wear was only seen in tissues around loosened prostheses with ceramic ceramic couples. Due to the material abrasion, a foreign body reaction rich in macrophages developed with minimal lymphocytic infiltration.The degree of these tissue alterations and the amount of wear particles showed a statistically significant increase with increasing implant duration. In contrast, fibrin exudates, hemorrhages, and metaplastic ossifications were not dependent on the length of time in situ. Differences in respect to the amount of wear particles were found between prostheses with ceramic and metallic heads. Prostheses with metal-polyethylene combinations generated approximately twice as many polyethylene wear particles as prostheses with ceramic heads. Among the metal-polyethylene couples, the bipolar prostheses showed a markedly increased polyethylene wear, some of them with extensive osteolyses. Deposits of calcium pyrophosphate were twice as common in pseudocapsules as in capsules from joints with degenerative arthrosis. Because of the increasing frequency of revision surgery, knowledge of the histologic changes around joint prostheses seems to be important as these changes may indicate complications and give information in respect to the biocompatibility of implant materials.     

Long-term follow-up study of bioactive bone cement for repairing a segmental defect in a canine femur

We report on a 7-year long-term follow-up study of a bioactive bone cement (BA cement) that was used to repair a segmental defect in a canine femur. Bilateral femoral segmental defects were repaired with metallic implants that were fixed to the femur using two kinds of bone cement. The BA cement used in this study consists of an apatite- and wollastonite-containing glass ceramic (AW-GC) with a bis-phenol-alpha-glycidyl methacrylate (bis-GMA)-based resin. The bone-cement interface was examined histologically. Previous short-term studies have shown that using BA cement for segmental replacement of the canine femur produced excellent biomechanical and histological results. The BA cement maintained the fixation of a metallic implant to the femur very well. In contrast, the PMMA cement did not maintain alignment under long-term weight-bearing conditions. The results of histological examinations showed direct bonding between the BA cement and bone, while an intervening soft tissue layer was observed at the bone-cement interface with the PMMA cement. The BA cement bonded to the bone through a Ca-P-rich reactive layer, which was twice as thick after 7 years than it was at 26 weeks. No adverse effects of BA cement were observed during the 7-year observation period.     

Osseointegrated Titanium Implants: Requirements for Ensuring a Long-Lasting, Direct Bone-to-Implant Anchorage in Man

A total of 2895 threaded, cylindrical titanium implants have been inserted into the mandible or the maxilla and 124 similar implants have been installed in the tibial, temporal or iliac bones in man for various bone restorative procedures. The titanium screws were implanted without the use of cement, using a meticulous technique aiming at osseointegration-a direct contact between living bone and implant. Thirty-eight stable and integrated screws were removed for various reasons from 18 patients. The interface zone between bone and implant was investigated using X-rays, SEM, TEM and histology. The SEM study showed a very close spatial relationship between titanium and bone. The pattern of the anchorage of collagen filaments to titanium appeared to be similar to that of Sharpey's fibres to bone. No wear products were seen in the bone or soft tissues in spite of implant loading times up to 90 months. The soft tissues were also closely adhered to the titanium implant, thereby forming a biological seal, preventing microorganism infiltration along the implant. The implants in many cases had been allowed to permanently penetrate the gingiva and skin. This caused no adverse tissue effects. An intact bone-implant interface was analyzed by TEM, revealing a direct bone-to-implant interface contact also at the electron microscopic level, thereby suggesting the possibility of a direct chemical bonding between bone and titanium. It is concluded that the technique of osseointegration is a reliable type of cement-free bone anchorage for permanent prosthetic tissue substitutes. At present, this technique is being tried in clinical joint reconstruction. In order to achieve and to maintain such a direct contact between living bone and implant, threaded, unalloyed titanium screws of defined finish and geometry were inserted using a delicate surgical technique and were allowed to heal in situ, without loading, for a period of at least 3-4 months.     

Soft tissue infection around a skin penetrating osseointegrated implant. A case report

A case is reported where a female patient with bilateral otosclerosis received a bone-anchored and skin-penetrating titanium implant on which a hearing aid was mounted to improve conductive hearing loss. The patient developed an infection that did not cease despite intensive local treatment and skin-grafting. Eventually the implant was removed. The histological examination of the interface between implant and surrounding bone and soft tissues showed an inflammatory reaction in the superficial parts of the soft tissues whereas the deeper portions of the soft tissues and all of the bone tissue were free of inflammation. It is concluded that it is possible to maintain osseointegration in spite of an aggressive soft tissue infection around the implant.     

Tissue response of apatite-filled resin cement and titanium-reinforced apatite dental implants in dogs

Abutment and root portion divided two-piece dental implants were designed to modify the one-piece dense hydroxyapatite (D-HAP) implant. The initial placement of the root portion endosseously ensured an aseptic environment and physical stability for the implant during the bone healing period. The outer D-HAP shell of the root portion was fortified by an inner titanium cylinder and cemented with an adhesive resin cement containing 4-methacryloyoxyethyl trimellitate anhydride (4-META) and reinforced by fine apatite filler. Upon attaining integration of the bone and implant, the abutment was screwed and fixed into the screw hole of the root portion. The tissue response of both the apatite-filled resin cement and root portion of the two-piece implant was studied by animal canine experiments. Light and electron microscopic examination of specimens taken from experimental animal tissue showed bone contacted directly not only the exposed apatite filler at the surface of the apatite-filled resin cement, but also the resin portion. These findings of direct bone contact suggested that the tissue response of apatite-filled resin cement was approximately similar to the usual D-HAP. Because most of the surface of the outer D-HAP shell of the root portion came in contact with bone, it prevented the deposition of contamination on the D-HAP surface during the manufacturing procedures of the root portion.     

Masquelet技术结合小腿皮瓣治疗胫骨感染性骨缺损伴广泛软组织缺损的疗效分析

目的:探讨Masquelet技术结合小腿皮瓣治疗胫骨感染性骨缺损伴广泛软组织缺损的疗效。方法:回顾性分析2016年3月至2019年6月解放军联勤保障部队第九二〇医院骨科采用Masquelet技术结合小腿皮瓣治疗的23例胫骨感染性骨缺损伴有广泛胫前软组织缺损患者资料。其中男15例,女8例;年龄18~59岁（平均38.4岁...     

Histologic and histomorphometric analysis of an immediately loaded implant retrieved from man after 14 months of loading

OBJECTIVE: The aim of this study was a histologic and histomorphometric analysis of the peri-implant tissue reactions and the bone/titanium interface in an immediately loaded titanium implant inserted in a soft bone site and retrieved, in man, after a 14-month loading period. METHODS. A 65-year-old patient presented with a partial edentulism in the left posterior mandible. The patient was rehabilitated with three dental implants inserted in the left first, second, and third molar sites. All these implants were immediately put into a nonfunctional loading mode and joined with the other implants that supported the temporary restorations. After 14 months, the most distal implant and surrounding tissues were retrieved because of psychological problems of the patient. RESULTS: Newly formed, strongly stained, compact, mature cortical bone with few marrow spaces was observed around the implant, especially in the coronal portion. No inflammatory infiltrate was present around the implant. No gaps or dense fibrous connective tissue were found at the bone/metal interface. No apical epithelial migration was found. In the cortical portion, bone remodeling areas were present with many newly formed Haversian canals. Only in a few areas of the interface was it possible to observe an osteoblast rim. In the apical portion, newly formed bone trabeculae were present; these were composed mostly by woven bone, and only a small quantity of preexisting lamellar bone was present. Histomorphometric evaluation showed that the bone/implant contact percentage was 72.6% (+/-2.7%). CONCLUSIONS: We found that, in immediately loaded implants inserted in soft tissue sites, it was possible to find a high percentage of bone-to-implant contact and that osseointegration was maintained for more than 1 year. This fact could be partly explained with the use of an implant with a rough surface.     

经皮椎体成形术治疗老年骨质疏松性胸腰椎压缩性骨折术中骨水泥渗漏的相关因素

目的分析经皮椎体成形术(PVP)治疗老年骨质疏松性椎体压缩性骨折(OVCF)术中骨水泥渗漏的相关危险因素。方法收集2015年1月—2017年12月采用PVP治疗的297例老年OVCF患者资料。采用logistic回归法分析年龄、性别、骨折部位、椎体压缩程度、椎体终板/后壁完整性、骨折节段数、骨水泥注射量与骨水泥渗漏(椎间盘、软组织、血管内、椎管内及混合渗漏)的关系。结果术中共166例发生骨水泥渗漏,渗漏率55.9%。二元logistic回归分析示骨水泥剂量高是骨水泥渗漏的唯一危险因素。多元logistic回归分析示椎体压缩程度高和骨折节段数多是椎间盘渗漏的危险因素;骨水泥注射量大和椎体压缩程度高是软组织渗漏的危险因素;女性和年龄较低是血管内渗漏的危险因素;骨水泥注射量大和椎体终板/后壁破裂是椎管内渗漏的危险因素。结论不同的危险因素导致PVP术中不同的渗漏类型。明确不同危险因素与各渗漏类型间的相互关系有利于防止骨水泥渗漏的发生。     

A qualitative and quantitative study of retrieved femoral heads in three different types of resurface hip arthroplasties

Tissue reactions and percentage of mineralized bone in three different types of retrieved femoral head hip resurface prostheses were studied in undecalcified ground sections without removing the metal. All of the prostheses demonstrated soft tissue between the cement-implant and bone. There were some areas without soft tissue between bone and cement. This bone was often not normally stained, indicating a disturbed mineralization. The soft tissue layer in the cemented prostheses was observed in different stages of necrosis, while the uncemented prostheses demonstrated a thick collagen membrane. One of the cemented groups demonstrated a gradual decrease of mineralized bone towards the cement. The uncemented implants revealed normal bone qualitatively and quantitatively when the bone bordering the prosthesis was excluded. Too high interfacial stresses were probably a major failure mechanism, especially in the rapidly failed noncemented prostheses. Negative long-term effects of the cement on the bone may have contributed to failure in the cemented resurface arthroplasties.     

Two-stage reconstruction with free vascularized soft tissue transfer and conventional bone graft for infected nonunions of the tibia: 6 patients followed for 1.5 to 5 years

Background?Vascularized soft tissue transfer may give better results of treatment of infected nonunions of the tibia.

Methods?6 patients with infected nonunion of the tibia and combined soft tissue (70–170?cm²) and bony (5–8?cm) defects underwent staged reconstruction. Initial surgery consisted of soft tissue and bone debridement, external fixation, filling of the bony defect with a gentamicin-impregnated cement spacer, and reconstruction of the soft tissue with a free microsurgical muscle flap and skin graft. Second-stage surgery consisted of removal of the cement spacer and osseous reconstruction with nonvascularized bone graft.

Results?All patients except 1 achieved full weight-bearing and radiographic consolidation after 7–10 months. This patient required repeated bone grafting and internal plate fixation to heal. There were no cases of recurrence of infection at the latest follow-up, after a mean of 3 (1.5–5) years.

Interpretation?Staged reconstruction with free vascularized soft tissue transfer and conventional bone grafting within a cement-induced membrane is a low-risk surgical strategy resulting in a high rate of bone healing.

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Two-stage reconstruction with free vascularized soft tissue transfer and conventional bone graft for infected nonunions of the tibia: 6 patients followed for 1.5 to 5 years

BACKGROUND: Vascularized soft tissue transfer may give better results of treatment of infected nonunions of the tibia. METHODS: 6 patients with infected nonunion of the tibia and combined soft tissue (70-170 cm(2)) and bony (5-8 cm) defects underwent staged reconstruction. Initial surgery consisted of soft tissue and bone debridement, external fixation, filling of the bony defect with a gentamicin-impregnated cement spacer, and reconstruction of the soft tissue with a free microsurgical muscle flap and skin graft. Second-stage surgery consisted of removal of the cement spacer and osseous reconstruction with nonvascularized bone graft. RESULTS: All patients except 1 achieved full weight-bearing and radiographic consolidation after 7-10 months. This patient required repeated bone grafting and internal plate fixation to heal. There were no cases of recurrence of infection at the latest follow-up, after a mean of 3 (1.5-5) years. INTERPRETATION: Staged reconstruction with free vascularized soft tissue transfer and conventional bone grafting within a cement-induced membrane is a low-risk surgical strategy resulting in a high rate of bone healing.     

Stress transfer at the femoral bone/bone cement interface as a function of the cement thickness

Summary When a cement canal prosthesis is used as the femoral component in total hip replacement (THR), the penetration depth of the bone cement can be varied according to the cement implantation pressure. Using experimental data which give a relation between the pressure applied to the cement at implantation and the resulting shape of the cement layer, a three-dimensional finite element study was performed to calculate the stress distribution at the bone/bone cement interface. The calculations show that the interface stresses increase with increasing depth of penetration by the cement layer. The explanation of this effect is that as the bone cement penetrates further into the cancellous bone, the cancellous bone is stiffened and can no longer act as a soft interposition between cortical bone and bone cement. From these results and from the clinical requirement that as little bone as possible be destroyed in any kind of alloarthroplasty, we conclude that the penetration depth of bone cement into cancellous bone in THR should be minimized to the depth necessary in order to achieve sufficient initial stability of the implant. The results show that a cement-canal prosthesis meets these requirements if a cement implantation pressure of 1.0 bar is used.     

Pseudomonas aeruginosa biofilm formation and slime excretion on antibiotic-loaded bone cement

Background Infection is an infrequent but serious complication of prosthetic joint surgery. These infections will usually not clear until the implant is removed and re-implantation has a high failure rate, especially when Pseudomonas aeruginosa is involved.

Material and methods We examined Pseudomonas aeruginosa biofilm formation on plain and gentami-cin-loaded bone cement with confocal scanning laser microscopy (CSLM). Two different stains were applied in order to visualize and quantify the distribution of bacterial cells and extracellular polymeric substances (slime) from the bone cement surface to the top of the biofilm. Staining with LIVE/DEAD viability stain differentiated between live and dead bacteria within the biofilm, and slime production was evaluated after staining with Calcofluor white.

Results CSLM showed that the biofilm was a nonuniform structure of variable thickness, with differences in local bacterial cell and slime densities. Incorporation of gentamicin in bone cement resulted in a 44% reduction in bacterial viability, while the slime density increased significantly. In addition, conventional plate counting showed the development of small-colony variants on gentamicin-loaded bone cement with a decreased sensitivity for gentamicin (MIC: 8 mg/L), as compared with normal-sized colonies taken from plain and gentamicin-loaded bone cement (MIC: 3 mg/L). The enhanced slime production on antibiotic-loaded bone cement, together with the formation of small-colony variants, resulted in decreased susceptibility to antibiotics—probably concomitant with the onset of persistent and relapsing infections.

Interpretation In the clinical situation, our findings help to explain the frequent re-implantation failure of joint replacements infected with P. aeruginosa when the procedure has been performed using antibiotic-loaded bone cement.     

Porous acrylic cement: evaluation of a novel implant material

The preparation and some properties of in situ curing porous acrylic cement, a modification of the traditional bone cement, are described. Through numerous animal experiments, the behavior of the porous cement in a biological environment has been studied. The histological evaluation reveals that hard and soft tissues readily grow into the pores of the cement, thus anchoring the implant to the host tissues. Some inflammatory foci, decreasing in number with residence time, together with varying numbers of multinucleated giant cells were found occasionally in the tissues in and around implants. When implanted in soft tissues, the porous cement behaved favorably with respect to solid acrylic implants because of the immobility of the implants and the absence of ectopic hard tissue formation. The biocompatibility of porous acrylic cement is judged to justify clinical trials in plastic and reconstructive surgery.     

Rekonstruktion ossärer Defekte mit der Masquelet-Technik

The Masquelet procedure or induced membrane technique presents a treatment option for relatively large osseous defects, e.g. after trauma, tumour resection or osteomyelitis even in the presence of unfavourable soft tissues. Initially developed at the end of the last century by the French surgeon Masquelet, the technique relies on a bioactive membrane that forms a foreign body reaction around a cement spacer. This spacer is implanted in the residual defect after rigorous debridement of bone and soft tissue during a first-stage procedure. A second-stage intervention is performed 1–2 months later with removal of the spacer under preservation of the membrane that has since formed around the cement. The membrane acts as an internal bioreactor exerting its effect via a rich vascularization and secretion of growth and differentiation factors. The void within the membrane is filled with an autologous cancellous graft. After adequate stabilisation using standard techniques, a gradual corticalisation of the graft can be observed over the duration of several months, with remodelling in the long-term course.The following article describes the original technique, our preferred approach including indication, surgical technique and postoperative follow-up. Additionally, the biological background and clinical tips and tricks are presented.     

Cement augmentation of hip implants in osteoporotic bone: How much cement is needed and where should it go?

Several studies proved the beneficial effect of cement augmentation of proximal femoral nail antirotation (PFNA) blades on implant purchase in osteoporotic bone. We investigated the effect of different localizations and amounts of bone cement. Polyurethane foam specimens were instrumented with a PFNA blade and subsequently augmented with PMMA bone cement. Eight study groups were formed based on localization and amount of cement volume related to the blade. All specimens underwent cyclic loading with physiological orientation of the force vector until construct failure. Foam groups were compared between each other and to a cadaveric control group. The experiments revealed a significant dependency of implant purchase on localization and amount of cement. Biomechanically favorable cement positions were found at the implant tip and at the cranial side. However, none of the tested augmentation patterns performed significantly inferior to the cadaveric benchmark. These findings will allow surgeons to further reduce the amount of injected PMMA, decreasing the risk of cement leakage or cartilage damage. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:362–368, 2014.     

Autopsy studies of the bone-cement interface in well-fixed cemented total hip arthroplasties

Although knowledge of the clinical status of the implant is important, only instrumented mechanical testing of retrieved specimens provides quantitative assessment of implant fixation. This measurement allows placement of the implant along a continuum of loosening and is the foundation for the interpretation of subsequent findings. Analysis of implants that have been proven to be well fixed by instrumented testing reveals significant differences in the initial events in the loosening of femoral and acetabular components. Although radiolucencies were observed around all of these well-fixed femoral and acetabular components, the histology (and therefore the etiology) of the radiolucency is different and variable on the two sides of the articulation. The majority of femoral radiolucencies appear to be due to age and stress-related remodeling while particulate-induced bone resorption plays an important role in acetabular radiolucencies. A finding common to both sides of the articulation in these stable components, however, was intimate contact of bone with cement without any interposed soft tissue even after 17.5 years of service. Primary incompatibility and/or failure of the cement was not identified as a factor in initiating either femoral or acetabular component loosening. These studies document the long-term compatibility of bone with cement in bulk form. Improvements in cemented femoral component fixation should focus on stem design and cementing technique. Long-term acetabular component fixation can be improved by reduction or elimination of polyethylene wear and optimization of the bone-implant interface.     

Complete orbit and forehead reconstruction using a free latissimus dorsi flap and MEDPOR implants

BACKGROUND: Reconstruction of enormous composite defects of the face in the presence of meningitis is a difficult problem. We present a case of a 29-year-old man with a huge, posttraumatic bone and soft tissue defect of the upper half of the left side of the face (orbit-zygoma-frontal-partial temporal bones), frontal lobe of the brain, and enucleated eye with intact facial skin. METHODS: An initial reconstruction using cement was complicated by multiple episodes of meningitis. In a multiple-stage procedure, we used a free latissimus dorsi muscle flap to re-construct the soft tissue defect and control the infection, a complete left orbit and frontal MEDPOR implant for the bone defect, and also an orbital sphere MEDPOR implant for the eyeball. RESULTS: In a 2-year follow-up, no infection was observed, and the cosmetic result is satisfactory. CONCLUSION: The combination of free flap and MEDPOR implants demonstrates an alternative method for reconstruction of complicated facial defects.     

In vivo loss of cement–bone interlock reduces fixation strength in total knee arthroplasties

Prevention of aseptic loosening of total knee arthroplasties (TKAs) remains a clinical challenge. Understanding how changes in morphology at the implant–bone interface with in vivo service affect implant stability and strength could lead to new approaches to mitigate loosening. Enbloc TKA retrievals and freshly‐cemented TKA tibial components were used to determine if the mechanical strength of the interface depended on the amount of cement–bone interlock and the morphology of the supporting bone under the cement layer. Implants were sectioned into small specimens of the cement–interface–bone from under the tibial tray. Micro‐CT scans were used to document interlock morphology and architecture of the supporting trabecular bone. Axial compression tests were used to assess mechanical behavior. Postmortem retrievals had lower contact fraction (42 ± 55%) compared to freshly‐cemented constructs (121 ± 61%) (p = 0.0008). Supporting bone architecture parameters were not different for the two groups. Increased interface contact fraction and supporting bone volume fraction (BV/TV) were positive predictors of interface strength (r² = 0.72, p = 0.0001). For the same supporting bone BV/TV, postmortem specimens had weaker interfaces; they were also more compliant. Cemented TKAs with in vivo service experience a loss of fixation strength and increased micro‐motion due to the loss of cement–bone interlock. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1052–1060, 2014.